data = list(map(int, input().split()))
def innerloop(s):
val=data[s]
while (s<len(data)):
if data[s] is not val:
break;
s+=1
e=s-1
return e
# make all '0'
cnt=0
idx=0
while(idx<len(data)):
if data[idx]==1:
print(idx, innerloop(idx))
idx=innerloop(idx)
cnt+=1
idx+=1
# make all '1'
while(idx<len(data)):
if data[idx]==0:
print(idx, innerloop(idx))
idx=innerloop(idx)
cnt+=1
idx+=1
data = list(map(int, input().split()))
res =data[0]
for idx in range(1,len(data)):
if data[idx]==0 or data[idx] ==1 or res ==0:
res+=data[idx]
else:
res*=data[idx]
print(res)